Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Fri, 2 Aug 2002 05:47:04 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Fri, 2 Aug 2002 05:47:04 -0400 Received: from nat-pool-rdu.redhat.com ([66.187.233.200]:8608 "EHLO devserv.devel.redhat.com") by vger.kernel.org with ESMTP id ; Fri, 2 Aug 2002 05:47:03 -0400 From: Alan Cox Message-Id: <200208020950.g729o3K28069@devserv.devel.redhat.com> Subject: Re: Accelerating user mode linux To: jdike@karaya.com (Jeff Dike) Date: Fri, 2 Aug 2002 05:50:03 -0400 (EDT) Cc: alan@redhat.com (Alan Cox), linux-kernel@vger.kernel.org In-Reply-To: <200208020440.XAA04793@ccure.karaya.com> from "Jeff Dike" at Aug 01, 2002 11:40:28 PM X-Mailer: ELM [version 2.5 PL6] MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 965 Lines: 19 > can't be an interrupt in the middle of that sequence. So, sys_switchmm > would also have to restore the old signal mask, which you'd have to pass > in unless you're going to read it off the signal frame. Also, it would > have to be open coded because you've already restored the stack pointer. Uggh.. you are right. You end up needing sigreturn handling > Your objection to returning through sigreturn was performance. Is performance > a veto of adding an mm switch to sigreturn, or it is possible to make it > acceptible? Its not a veto. I was trying to avoid having to add any more branches to the fast paths in the kernel. The remaining sigreturn question is "how do you get into 'user' mode the first time" - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/